Because of the large number of HCV infected individuals worldwide, therapeutic drugs are critically needed. Currently, it is not possible to efficiently propagate HCV in culture, or to generate actively infected non-primate animal models of the disease.
The efforts to develop therapeutic drugs against HCV would be aided by the establishment of cell lines that carry replicating HCV RNA or synthesize de novo HCV virus. In particular, a reproducible system which accommodates replication of sub-genomic RNA would facilitate drug screening. However, no such system currently exists that is both robust and amenable to drug screening applications. Recently, Lohmann et al. (1999, Science, 285:110–113) described neomycin-selectable, HCV sub-genomic replicons, which were used to establish a few stable cell clones producing autonomously replicating sub-genomic HCV RNAs, in Huh-7 cells. Lohmann et al. report that efficiency of recovery, however, was low, and speculate that recovery was due to particular host cell conditions or factors present in only a few cells.
The present invention is directed to a cell-based system to establish the replication of sub-genomic viral replicons, such as that of HCV, with high efficiency.